The present invention relates to electrical connectors, and in particular to switchable electrical connectors. The present invention also relates to amplifying devices positioned along RF (e.g., CATV) cable, and power coupling equipment used to selectively distribute AC power to such devices over RF cable.
CATV signals are typically distributed from a centrally located station (headend) over long cables to a number of sub-stations (remote hubs), and then from the remote hubs through relatively short feeder lines to the individual receiving locations, e.g. residences. Most conventionally, the CATV signal is transmitted over coaxial cable as an RF signal.
The distribution of CATV signals as RF signals involves the positioning of various electrical signal amplifying devices (e.g., trunk amps, distribution amps and line extenders) along the CATV lines. These devices require electrical power to operate. For example, line extenders must be positioned along the lines at fixed intervals in order to compensate for line losses and thereby maintain proper signal strength. Typically, AC power is provided to line extenders and other amplifying devices positioned along the lines from an external source connected to the RF cable through an AC power coupler (power inserter). In this manner, each power source can power a number of amplifying devices along the line, and additional electrical lines for transmitting power to the devices are avoided. Within each line extender, the AC power signal is tapped and converted by an internal power supply to DC for application to the amplifying circuitry. In some applications, the AC power signal may be passed into the line extender through the RF input port. In other cases, the AC signal may enter through the RF output port. In either case, transmission of the AC power signal may be terminated at the line extender, or it may be desired to power another line extender or other equipment down the line by passing a portion of the signal back into the RF cable. Heretofore, a simple and compact arrangement has not existed for providing the aforementioned switching flexibility. A conventional arrangement requires a printed circuit board having two three-hole sockets, and two respective two pin plugs (a separate plug and socket arrangement associated with both the RF input and RF output). The two plugs are movable between block and pass positions defined by the sockets to accomplish the described switching
A power inserter supplies AC power from an external AC power source, to the RF cable at selected locations. Depending on the particular application, it may be desirable to supply the AC power signal to devices positioned in one or both directions of the RF cable. Alternatively, in certain instances, it may be desirable to pass AC power through the power inserter, by-passing the AC power source. Heretofore, a simple and compact arrangement has not existed for providing such switching flexibility. A conventional arrangement places fuses in branched lines leading from the AC power source to each of two AC/RF couplers/decouplers in order to protect the amplifier circuitry from excessive currents from the AC power source. The fuses are removable to prevent AC power transmission in one or both directions of the RF cable. In addition to taking up excessive board space and requiring numerous components, this arrangement does not readily allow AC power to pass through the power inserter while the AC power source is by-passed.